New shoes for the RR

[MarcR]

Any significant MPG decrease OP as the Falken AT4 is much heavier than KO3?

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[Putz173]

I drive 95% in town so probably not much difference, Id certainly be looking at something lighter and more eco friendly than a beefy AT if i was commuting, im sure they will hurt MPG a bit with the weight, but in my case its a wash, new wheels are lighten the OEM, tires are heavier than OEM lol

 

[Daweism]

What load range did you go with? I know the SL is actually a few pounds lighter than the stock KO3.

 

[Putz173]

went with C rated, I wanted lighter tires but i drive on cut corn fields in the fall and those are hard on sidewalls as ive found out in the past lol

 

[Raptor Family]

53lb tire + my 25.2lb Method 705s is 78lbs vs. stock KO3s on beadlocks that weighed a whopping 92lbs.

Thats a massive 56lbs less in rotating mass, no change in tire diameter so I dont need a lift and I get a much bigger tire look which mostly comes from the added width, not the diameter.

That is a lot of rotational mass you have lowered. It will make your truck accelerate faster. But more importantly, it will also stop faster. If you ever did a massive 4wd burn out at speed—those spinning wheel are like huge flywheels with lots of spinning energy—if you get slightly bent out of shape—you can’t stop them fast enough.
In the Bronco forum, they were dyno testing different wheel and tire weights. Shedding 20lbs per wheel (measuring only 2 wheels on Dyno) gained them 25whp. Now, you can tell everybody it goes faster and, the unsprung weight will make the suspension handle better. In the real world, you have 4 wheels on the road instead of the Dyno—it’s better all around.
PS:: I like the color of those Methods with the color of your truck.

 

[Lion77]

Yep, rotational mass sucks power because you waste energy accelerating the rotating mass in it's circular pattern but then also moving that mass along an axis.

So not only is the wheel being moved from point A to point B along the road, but it has to be spun up during that process and the more mass it has, the less available energy from the engine goes to moving the whole vehicle.

Someone on this forum tried to argue endlessly about how wheel / tire mass had no effect on power, he just couldn't grasp the reality that it wasn't power output from the engine that was changing, it was how effectively the power was being used.

Since my build is focused more on how Ford envisioned the Ranger Raptor, for now I'm actually going the opposite of what many do, lighter wheels so they can off-set the weight of bigger tires, which is fine. But I'm actually trying to go lighter than the stock setup to increase overall performance.

The Bronco is the crawler, 37" tires, short wheel based in an SUV format, it's clearly optimized for crawling, but stock to stock it's over 1/2 second slower than the RR. The F-150 Raptor is the big desert Baja truck that serves double duty as a legitimate work truck, 6 foot bed, SCREW in a full-sized chassis, but it's size is enormous and it just isn't as nimble, but can go over bigger obstacles, especially with 37's.

The Ranger is the ONLY truck with a Watts link, it was developed by the Aussie team focused on Rally racing, which is why it handles corners at higher speeds better than both it's big brothers, it's also 600lbs lighter than the F-150 and has the lowest ground clearance at 10.7 in but also the lowest CG. And 10.7in minimum running clerance is not bad, that's standard for off-road mid-sizers across the industry. Taco's, Jeeps, Colorado's are all in the high 10's to low 11 in range stock.

But the RR is clearly set up for higher speed driving and handling dynamics. The team driver at Finke said they ran the pre-runner RR with stock 33's at Finke since there was no issue with ground clearance due to it being a smoother higher speed track than Baja, so they only went with 35's on the RR race truck for ground clearance at Baja due to it being so heavily rutted and just kept that at Finke instead of changing tires and messing with suspension tuning, but 33's are faster for braking, acceleration, turn-in response and easier on the drive train. The RR race truck had a compromised suspension setup just to run 35's and the driver liked the STOCK pre-runner MORE in terms of handling, he was actually asking the team mechanics to try and dial it in so it was more like the stock pre-runner.

The race truck also broke a diff at Finke in 25' and I suspect the 35x12.5's were the cause, all that mass and diameter on the whoops was just hammering the front diff. I'll bet my bottom dollar that if it was on 33's and lighter wheels, the diff would not have failed. It's all about trade-offs, the real advantage of big tires comes in smoother ride over rougher terrain and ground clearance.

The drawback is added stress on the drivetrain, lots of added mass that slows acceleration, braking, more sluggish turn-in, poorer fuel economy, greater thermal loading on the engine and drivetrain etc. I'm not racing Baja though nor am I crawling with it, I use my truck for a wide variety of things, including towing, so 33" are more appropriate as the do-it-all off-road tire for now.

33's are also on the F-150 Tremor, the Silverado 1500 ZR2 as the balance between full work-truck capability and off-roading. It's still a very versatile tire size and while 35's do add some capability off-roading, it's nuanced for specific situations, where 95% of the time it's not helping. Width gives you flotation, not diameter, so even for flotation you don't NEED to go to 35's. 35's shine in rought terrain at slower speeds, 33's shine on smoother terrain at higher speeds and for practical uses like utility applications which is why the F-150 Tremor and Silverado 1500 ZR2 full sized trucks still run 33's so they can still have max towing capability.

If I ever retire the truck from general purpose utility vehicle to a "weekend toy racer", I may consider 35's / lifts etc. because it's now singularly focused only for off-road performance, but as long as I need it to do a wide variety of activities and want to maintain warranty, do family trips, home depot runs, towing and considering the places I enjoy driving allow higher speeds anyway on somewhat smoother terrain (i.e., dirt fire roads, gravel roads, sand dunes, farm fields, back country paved roads in Amish country), there's no advantage to larger tires for my uses and I'd rather have the advantages in acceleration, braking, fuel economy and handling.

 

[Putz173]

I wish the Falken at4 C load werent quite so heavy, but I dont want an E rated 10 ply as they are just too stiff for these trucks (and heavier yet again)

SL would have been ideal but ive put a couple dried corn stalks through my sidewalls in the past hunting and crossing fields so these seemed like a good comprimise for now, SL sucks for towing with the tall sidewalls they move around alot

that said these trucks have so much torque im not sure how much we will notice the acceleration, im sure a stop watch or track will tell you

 

[Lion77]

We'll see how the Pirelli XTM AT's ride on E load. All the demo cars they used them on, which was Jeeps and Bronco's, had the E load rated 285/70R17s. The reviews said that tire in E load was pretty comparable to the stock KO3 in C load.

I think the sidewall construction, compounds and carcas all play significant roles into how the tire rides from mfg. to mfg. Maybe Pirelli's E load just rides better than BFG's or Falken's, at least based on several reviews I've seen so far on those tires.

What I like about the XTM's is they have the same off-road grip as the KO3's, but more precise steering on-road and more predictable brake away at the limits of traction. The KO3's are good until their not, once they let go, recovery is difficult which is one of their negatives.

And the XTM's are only 53lbs per tire as mentioned, with about the same tread width as the AT4's, arguably an even more aggressive sidewall design, but we'll see once I get to the point of needing new tires as I'm not there yet.

 

[saf1]

Yep, rotational mass sucks power because you waste energy accelerating the rotating mass in it's circular pattern but then also moving that mass along an axis.

So not only is the wheel being moved from point A to point B along the road, but it has to be spun up during that process and the more mass it has, the less available energy from the engine goes to moving the whole vehicle.

Someone on this forum tried to argue endlessly about how wheel / tire mass had no effect on power, he just couldn't grasp the reality that it wasn't power output from the engine that was changing, it was how effectively the power was being used.

Since my build is focused more on how Ford envisioned the Ranger Raptor, for now I'm actually going the opposite of what many do, lighter wheels so they can off-set the weight of bigger tires, which is fine. But I'm actually trying to go lighter than the stock setup to increase overall performance.

The Bronco is the crawler, 37" tires, short wheel based in an SUV format, it's clearly optimized for crawling, but stock to stock it's over 1/2 second slower than the RR. The F-150 Raptor is the big desert Baja truck that serves double duty as a legitimate work truck, 6 foot bed, SCREW in a full-sized chassis, but it's size is enormous and it just isn't as nimble, but can go over bigger obstacles, especially with 37's.

The Ranger is the ONLY truck with a Watts link, it was developed by the Aussie team focused on Rally racing, which is why it handles corners at higher speeds better than both it's big brothers, it's also 600lbs lighter than the F-150 and has the lowest ground clearance at 10.7 in but also the lowest CG. And 10.7in minimum running clerance is not bad, that's standard for off-road mid-sizers across the industry. Taco's, Jeeps, Colorado's are all in the high 10's to low 11 in range stock.

But the RR is clearly set up for higher speed driving and handling dynamics. The team driver at Finke said they ran the pre-runner RR with stock 33's at Finke since there was no issue with ground clearance due to it being a smoother higher speed track than Baja, so they only went with 35's on the RR race truck for ground clearance at Baja due to it being so heavily rutted and just kept that at Finke instead of changing tires and messing with suspension tuning, but 33's are faster for braking, acceleration, turn-in response and easier on the drive train. The RR race truck had a compromised suspension setup just to run 35's and the driver liked the STOCK pre-runner MORE in terms of handling, he was actually asking the team mechanics to try and dial it in so it was more like the stock pre-runner.

The race truck also broke a diff at Finke in 25' and I suspect the 35x12.5's were the cause, all that mass and diameter on the whoops was just hammering the front diff. I'll bet my bottom dollar that if it was on 33's and lighter wheels, the diff would not have failed. It's all about trade-offs, the real advantage of big tires comes in smoother ride over rougher terrain and ground clearance.

The drawback is added stress on the drivetrain, lots of added mass that slows acceleration, braking, more sluggish turn-in, poorer fuel economy, greater thermal loading on the engine and drivetrain etc. I'm not racing Baja though nor am I crawling with it, I use my truck for a wide variety of things, including towing, so 33" are more appropriate as the do-it-all off-road tire for now.

33's are also on the F-150 Tremor, the Silverado 1500 ZR2 as the balance between full work-truck capability and off-roading. It's still a very versatile tire size and while 35's do add some capability off-roading, it's nuanced for specific situations, where 95% of the time it's not helping. Width gives you flotation, not diameter, so even for flotation you don't NEED to go to 35's. 35's shine in rought terrain at slower speeds, 33's shine on smoother terrain at higher speeds and for practical uses like utility applications which is why the F-150 Tremor and Silverado 1500 ZR2 full sized trucks still run 33's so they can still have max towing capability.

If I ever retire the truck from general purpose utility vehicle to a "weekend toy racer", I may consider 35's / lifts etc. because it's now singularly focused only for off-road performance, but as long as I need it to do a wide variety of activities and want to maintain warranty, do family trips, home depot runs, towing and considering the places I enjoy driving allow higher speeds anyway on somewhat smoother terrain (i.e., dirt fire roads, gravel roads, sand dunes, farm fields, back country paved roads in Amish country), there's no advantage to larger tires for my uses and I'd rather have the advantages in acceleration, braking, fuel economy and handling.

Nice write up, thanks.

Side note - just caught the disgruntled former 2016 Mustang comment in the sig. Why is that if you don't mind me asking? Loved my 2015 gt/pp. Wish I kept it. Wanted a gt350 but the dealer ADM was just instance at the time due to demand.

 

[Daweism]

Yep, theres a thread from an aussie guy showing two RR next to each other, one bone stock on stock KO3s, the other modified on 33x12.5 Maxxis razors and even though the 33x12.5 is a measly 0.2 in bigger diameter they look huge next to the stock KO3s.

Im going to give the Pirrelli XTM ATs a try once my KO3s are worn out since they have the same tread width as the AT4Ws, but a much lighter weight, even lighter than the stock KO3s.

53lb tire + my 25.2lb Method 705s is 78lbs vs. stock KO3s on beadlocks that weighed a whopping 92lbs.

Thats a massive 56lbs less in rotating mass, no change in tire diameter so I dont need a lift and I get a much bigger tire look which mostly comes from the added width, not the diameter.

You can also try the SL load range for the AT4W

The Falken Wildpeak A/T4W in size 285/70R17 weighs 53.4 lbs for the Standard Load (SL) version and 65.4 lbs for the Load Range C

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